ECE 2212
PROBLEM SET 5
S. G. Burns
Due: Wednesday, 5 March 2014
Note 1: I
am adjusting the schedule and topical coverage because of the snow day on
Friday, 21 February. This Problem Set 5
will be due on Wednesday, 5 March. Quiz 5
will also be administered on 5 March.
There will not be a quiz or problem set due this week (24-28 February.
Note 2:
Several of the problems are include designs. I strongly encourage that you start this
problem set in
a timely manner!
1.
Text 3.72 Part (a) assumes
you assume the diode switches from OFF to ON when the diode voltage is zero
volts. Part (b) of problem assumes you use the diode model that just includes a
0.7 volt battery when the diode switches from OFF to ON. The best approach is
to draw out each circuit and then look for any potential contradictions with
the diode model and circuit when you assume a diode is either ON or OFF.
Sketching a piece-wise linear I-V characteristic is one approach to piece-wise
linear problems. Prepare a table to summarize your results.
2.
Text 3.21 This is very similar to the parameter
extraction you addressed in Experiment
3, 20 February.
3.
Based on an old quiz problem.
You are to design a battery charger for safe operation in a damp garage
environment to
use for charging your 12 VDC car
battery.
Design, that is provide a detailed and
well-labeled circuit diagram,
a dc power supply to accomplish this objective
by
satisfying the following design goals:
(a)
Input
is a 110rms
VAC. (VP=110x 
) at 60 Hz from a three wire service that meets
the National Electrical Code.
(b)
Output
is a nominal 14.4 VDC
(c)
Specify
a resistor, R, to
limit the maximum battery charging current to 10 amperes.
(d)
Use
a half-wave rectifier.
(e)
There
is no ripple voltage design specification.
Explain why this is unnecessary in this application.
(f)
Use
a transformer .
(g)
The
battery charger case is metal.
(h)
Assume
a diode with VF = 0.7 V
(i)
Use
a correctly located fuse in the primary circuit to protect the power supply
from a short-circuit at the battery terminals either
from total battery failure or accidentally short 
circuiting the charging cable to ground. (For
example, dropping a wrench across the battery terminals-oops!).
(j)
A
voltage regulator is not required
Your Design must include:
Well-labeled circuit diagram including the identification of the incoming “hot”, “neutral”, and “ground wires (U.S. standards)
including the National Electric Code color coding of these wires and also show
the correct color-coded wiring for a standard grounded duplex receptacle and
plug.
i.
Key
design equations and supporting calculations
ii.
Component
specifications including:
iii.
Transformer-turns
ratio
iv.
Diode-current
and power ratings
v.
Your
assessment and short discussion as to whether the laboratory 1N4001 diodes
would work or not.
vi.
Value
for R
vii.
Current
rating of a fuse to protect the power supply against a short circuit condition
at the battery terminal.
4.
Similar to an old quiz
problem. Your design team is to design a +40
volt dc power supply for your home sound
system. Your sound system requires a 400 watt
capability. The power supply is
energized from a three-wire 110 Vrms 60 Hz power line
that meets the National Electric Code (NEC).
The system
block diagram and design specifications are given below.
